<?php

/**
 * Twitter-API-PHP : Simple PHP wrapper for the v1.1 API
 *
 * PHP version 5.3.10
 *
 * @category Awesomeness
 * @package  Twitter-API-PHP
 * @author   James Mallison <me@j7mbo.co.uk>
 * @license  MIT License
 * @link     http://github.com/j7mbo/twitter-api-php
 */
class TwitterAPIExchange {
	private $oauth_access_token;
	private $oauth_access_token_secret;
	private $consumer_key;
	private $consumer_secret;
	private $postfields;
	private $getfield;
	protected $oauth;
	public $url;

	/**
	 * Create the API access object. Requires an array of settings::
	 * oauth access token, oauth access token secret, consumer key, consumer secret
	 * These are all available by creating your own application on dev.twitter.com
	 * Requires the cURL library
	 *
	 * @param array $settings
	 */
	public function __construct( array $settings ) {
		if ( ! in_array( 'curl', get_loaded_extensions() ) ) {
			throw new Exception( 'You need to install cURL, see: http://curl.haxx.se/docs/install.html' );
		}

		if ( ! isset( $settings['oauth_access_token'] )
			|| ! isset( $settings['oauth_access_token_secret'] )
			|| ! isset( $settings['consumer_key'] )
			|| ! isset( $settings['consumer_secret'] )
		) {
			throw new Exception( 'Make sure you are passing in the correct parameters' );
		}

		$this->oauth_access_token        = $settings['oauth_access_token'];
		$this->oauth_access_token_secret = $settings['oauth_access_token_secret'];
		$this->consumer_key              = $settings['consumer_key'];
		$this->consumer_secret           = $settings['consumer_secret'];
	}

	/**
	 * Set postfields array, example: array('screen_name' => 'J7mbo')
	 *
	 * @param array $array Array of parameters to send to API
	 *
	 * @return TwitterAPIExchange Instance of self for method chaining
	 */
	public function setPostfields( array $array ) {
		if ( ! is_null( $this->getGetfield() ) ) {
			throw new Exception( 'You can only choose get OR post fields.' );
		}

		if ( isset( $array['status'] ) && substr( $array['status'], 0, 1 ) === '@' ) {
			$array['status'] = sprintf( "\0%s", $array['status'] );
		}

		$this->postfields = $array;

		return $this;
	}

	/**
	 * Set getfield string, example: '?screen_name=J7mbo'
	 *
	 * @param string $string Get key and value pairs as string
	 *
	 * @return \TwitterAPIExchange Instance of self for method chaining
	 */
	public function setGetfield( $string ) {
		if ( ! is_null( $this->getPostfields() ) ) {
			throw new Exception( 'You can only choose get OR post fields.' );
		}

		$search  = array( '#', ',', '+', ':' );
		$replace = array( '%23', '%2C', '%2B', '%3A' );
		$string  = str_replace( $search, $replace, $string );

		$this->getfield = $string;

		return $this;
	}

	/**
	 * Get getfield string (simple getter)
	 *
	 * @return string $this->getfields
	 */
	public function getGetfield() {
		return $this->getfield;
	}

	/**
	 * Get postfields array (simple getter)
	 *
	 * @return array $this->postfields
	 */
	public function getPostfields() {
		return $this->postfields;
	}

	/**
	 * Build the Oauth object using params set in construct and additionals
	 * passed to this method. For v1.1, see: https://dev.twitter.com/docs/api/1.1
	 *
	 * @param string $url The API url to use. Example: https://api.twitter.com/1.1/search/tweets.json
	 * @param string $requestMethod Either POST or GET
	 *
	 * @return \TwitterAPIExchange Instance of self for method chaining
	 */
	public function buildOauth( $url, $requestMethod ) {
		if ( ! in_array( strtolower( $requestMethod ), array( 'post', 'get' ) ) ) {
			throw new Exception( 'Request method must be either POST or GET' );
		}

		$consumer_key              = $this->consumer_key;
		$consumer_secret           = $this->consumer_secret;
		$oauth_access_token        = $this->oauth_access_token;
		$oauth_access_token_secret = $this->oauth_access_token_secret;

		$oauth = array(
			'oauth_consumer_key'     => $consumer_key,
			'oauth_nonce'            => time(),
			'oauth_signature_method' => 'HMAC-SHA1',
			'oauth_token'            => $oauth_access_token,
			'oauth_timestamp'        => time(),
			'oauth_version'          => '1.0'
		);

		$getfield = $this->getGetfield();

		if ( ! is_null( $getfield ) ) {
			$getfields = str_replace( '?', '', explode( '&', $getfield ) );
			foreach ( $getfields as $g ) {
				$split              = explode( '=', $g );
				$oauth[ $split[0] ] = $split[1];
			}
		}

		$func                     = 'base64' . '_encode';
		$base_info                = $this->buildBaseString( $url, $requestMethod, $oauth );
		$composite_key            = rawurlencode( $consumer_secret ) . '&' . rawurlencode( $oauth_access_token_secret );
		$oauth_signature          = $func( hash_hmac( 'sha1', $base_info, $composite_key, true ) );
		$oauth['oauth_signature'] = $oauth_signature;

		$this->url   = $url;
		$this->oauth = $oauth;

		return $this;
	}

	/**
	 * Perform the actual data retrieval from the API
	 *
	 * @param boolean $return If true, returns data.
	 *
	 * @return string json If $return param is true, returns json data.
	 */
	public function performRequest( $return = true ) {
		if ( ! is_bool( $return ) ) {
			throw new Exception( 'performRequest parameter must be true or false' );
		}

		$getfield   = $this->getGetfield();
		$postfields = $this->getPostfields();

		$args = array(
			'headers'     => array(
				'Authorization' => $this->buildAuthorizationHeader( $this->oauth ),
			),
			'redirection' => 0,
		);

		$url = $this->url;
		if ( ! is_null( $postfields ) ) {
			$args['method'] = 'POST';
			$args['body']   = $postfields;
		} else {
			$args['method'] = 'GET';
			if ( $getfield !== '' ) {
				$url .= $getfield;
			}
		}

		$response = wp_remote_request( $url, $args );
		$json     = wp_remote_retrieve_body( $response );
		if ( $return ) {
			return $json;
		}
	}

	/**
	 * Private method to generate the base string used by cURL
	 *
	 * @param string $baseURI
	 * @param string $method
	 * @param array $params
	 *
	 * @return string Built base string
	 */
	private function buildBaseString( $baseURI, $method, $params ) {
		$return = array();
		ksort( $params );

		foreach ( $params as $key => $value ) {
			$return[] = "$key=" . $value;
		}

		return $method . "&" . rawurlencode( $baseURI ) . '&' . rawurlencode( implode( '&', $return ) );
	}

	/**
	 * Private method to generate authorization header used by cURL
	 *
	 * @param array $oauth Array of oauth data generated by buildOauth()
	 *
	 * @return string $return Header used by cURL for request
	 */
	private function buildAuthorizationHeader( $oauth ) {
		$return = 'OAuth ';
		$values = array();

		foreach ( $oauth as $key => $value ) {
			$values[] = "$key=\"" . rawurlencode( $value ) . "\"";
		}

		$return .= implode( ', ', $values );

		return $return;
	}
}
